1. Field of the Invention
The invention relates to a method for determining the characteristic properties of soot particles from combustion processes by way of determining the blackening of a filter paper.
2. The Prior Art
Smoke meters of the current generation establish the filter smoke number (FSN) or the soot emission in mg/m3 by means of the deposition of particles on a filter paper. Due to the possibility of varying the suction length and suction time, it is possible to vary the measuring range in the context of such a method within very wide limits. The measured values range approximately from FSN 0.001 to 10, which corresponds to measured concentration values of approximately 0.015 to 30000 mg/m3.
But measuring the size of the emitted particles is, on the one hand, either quite time-consuming or quite complex and, on the other hand, in part very expensive equipment is necessary for the process. Examples of equipment of this kind include impactors, however, they have the disadvantage of long measuring times and the requirement of having to weigh the collected particles; electrical low pressure impactors (ELPI), a low-pressure impactor type with dynamic measurement; and particle mobility analyzers such as scanning mobility particle sizers (SMPS) or double differential mobility particle sizers (DDMPS), etc.
Currently, the composition of the particles can only be established either by way of chemical extraction—with diverse solvents, such as dichloromethane—or by way of thermogravimetric methods, which means by way of sample heating. To this end, the particles must be collected in a defined filter, weighed and submitted for analysis according to one of the methods referred to above—including weighing of the filters following the filter treatment.
The object of the present invention therefore consists in providing a method that allows for the simple, quick and relatively accurate determination of the particle sizes and possibly of further characteristics as well.